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Airbus E-Fan Electric Aircraft Makes First Flight
An anonymous reader writes "The aviation industry has taken a tentative step toward electric power with the successful maiden flight of the Airbus E-Fan. The manufacturer known for the massive A380 jetliner began testing this small experimental aircraft last week, with the ultimate aim of lowering the huge carbon dioxide emissions from commercial flights. The E-FAN is powered by 120 lithium-polymer batteries, and can fly at speeds up to 136mph. Measuring just 19 feet from nose to tail, the compact aircraft show that Airbus probably isn't ready for commercial zero emissions flight just yet, but it does highlight the potential benefits."
For this version of the plane.
http://en.wikipedia.org/wiki/A...
Great range, zero emissions, they've already been tested.
This is very doable.
http://en.wikipedia.org/wiki/N...
And I don't see any potential downsides
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If it was so practical, why did they wholly cut funding. Seems like they had a long way to go to make the nuclear design feasible to where the crew was safe.
And how many civilians would fly with a nuclear reactor?
Replacing the nuclear reactor with batteries means A LOT of batteries. So I'm not sure how you can claim the whole idea is feasible just from a working nuclear design.
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" lowering the huge carbon dioxide emissions from commercial flight" - Until the energy density of batteries goes up and and we have an efficient, carbon dioxide free way to charge them, I'm not sure I see the value here.
Exactly. I don't see why they bothered in the first place. They should quit. Now.
The aft main wheel includes an electric motor with 6kW power, which provides taxiing and acceleration up to 60km/h during the take-off
This may give the "plane on a treadmill" problem a bit more traction.
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in my area, which has the busiest airport in the world some years (other LAX takes the title), we get 55 percent of our power from nuclear energy
Electric vehicles are not (necessarily) zero emission - you need to consider where the electricity used to charge the batteries comes from.
All from wind and hydro? Not bad (depends on how much fossil fuel went into the construction of that wind and hydro, so not necessarily zero emission but close). All from the coal plant? Ermmm...not so much.
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Just what the doctor ordered after what happened with the 787.
With only 45 minutes to one hour of flight time I don't see how this is considered viable or even safe.
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Using electric vehicles (planes, trains or automobiles) is not just about shifting the CO2 emission point.
It allows use of energy sources that would not otherwise be viable for transportation (liquid hydrocarbons have a significant premium over other forms such as gas or solids). In addition land based power facilities have significantly higher efficiencies (open cycle gas turbines are lucky to get 40% efficiency, stick a waste heat recovery boiler on the back end and it is up to 60% efficiency).
The other alternative fuel for air transport I can see would be LNG (liquified natural gas), at that point we need several generations of improvement in scramjet technologies (air breathing rockets anyone?).
That's still a good amount of time to be useful for things like island hopping.
The article states endurance between 45 minutes and 1 hour. But lets be optimistic and assume 1 hour ...
... maybe a 60 mile one way (plane stays and has time for recharge) or 25 mile round trip (plane immediately returns)?
:-)
Not all that time is "available", at *least* 20 minutes should be reserved for safety. Lets subtract 5 minutes at each end for traffic patterns. So we're really looking at something closer to 30 minutes in practice.
Once you factor in taxiing, climb, descent, etc
Now if you are being pessimistic and going with a 45 minute endurance then we're looking at about 15 minutes in practice. Maybe a 25 mile one way flight?
Yes those numbers are not linear. The difference between 1 hour and 45 minute duration is coming entirely out of cruise time. Safety margin, traffic, ascent, descent, taxiing, etc are unchanged.
That said, this aircraft is incredible. But it is only a technology demonstrator.
However it should be awarded bonus points for resembling the A-10 a little.
So which is worse - carbon footprint or trying to dispose of nuclear waste. Either way, there is no such thing as a zero-emission engine. Somewhere there is something that is creating waste products that have to be dealt with.
4th generation nuclear reactors will use the waste of previous generation reactors as fuel. So dealing with current waste is storing it for 30 years until the 4th gen reactors arrive commercially (research reactors are already running) and can burn it up as fuel. The waste from the 4th gen is far less dangerous and only remains hazardous for a few hundred years rather than tens of thousands.
3rd gen reactors are starting commercial construction and while they don't have the waste/fuel benefits of 4th gen they are much safer than previous generations.
The electric motor really doesn't change the difficulty of flying. In a small training aircraft, engine management is a very minor part of the workload.
With only 45 minutes to one hour of flight time I don't see how this is considered viable or even safe.
Well if you consider it a technology demonstrator its pretty impressive, and that is all it is claimed to be. Plus it gets bonus points for resembling an A-10, see pictures from front.
Range probably isn't a real issue as it is offered as a 'trainer'. But a trainer should be paying for itself and this will spend too much time on the charger for that.
But the flight school won't be impressed with 45 min flight and an hour (is that all?) on the ground to recharge. On good days (and this isn't a bad day plane) we turned around the small trainers in minutes for the next student. Unless this is half the price for half the flight time it's just another feel-good product that no one will actually buy.
Now we could have used one of these I suppose, but it would have been 1 of these mixed with several Cessnas and several others. Unique enough to get some use most likely. Any operation with only a couple trainers wouldn't want this as one of them with the limited flight time available. Spending more than half its time on the ground makes a pretty sucky trainer too.
With no info on handling, it may not even be much of a trainer anyway. The Grumman Americans we used were marketed as a 'trainer' also but were not for everyone.
Jet fuel has at least 50 times the energy density of lithium batteries ...
And various aircraft ranging from a Boeing 777 to a US Navy F/A-18 have been flown using aviation biofuel, carbon neutral. Its experimental an hellaciously expensive but its a more realistic future.
Probably. But this thing is a prototype. The infrastructure for supplying Hydrogen to airports will not be in place until such a plane is commercialised.
Can we please stop trying to insinuate that electric vehicles do not have a carbon footprint?
Until the energy density of batteries goes up and and we have an efficient, carbon dioxide free way to charge them, I'm not sure I see the value here.
Sort-of agree, and energy density is definitely a problem with batteries in any application. However, batteries make a LOT of sense when it comes to a carbon-neutral way to charge them. With a conventional engine you're almost always limited to fossil fuels. With a battery you could still end up burning coal to charge, but you've decoupled the ultimate power source from the plane so you don't HAVE to use fossil fuels. The battery could be charged by nuclear, even though you could never put a reactor on a plane.
I doubt we'll see an electric airliner anytime soon. Where you might see them is for recreational aircraft. Many pilots just buzz around locally for a while and land, and battery power might be ideal for this - there is no urgency to refuel quickly, maintenance could be lower, aircraft could be quieter, no leaded fuel, cheaper costs, etc.
I agree. Airbus spent some money on a fun little project.
Yeah, if you just replace the back seat occupant with an equivalent mass of batteries, you could get twice the range.
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It's as beneficial as sailing on top of a rock. No carbon footprint there either!
I have no idea if this would help, but with developments in solar technology, would it make a significant difference if the tops of the wings, fuselage, tail and fan ducts were all solar panels? Seems like a simple thing to do to help with range... maybe not done because it's not reliable.
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At least having no avgas there will be a few less items on the checklist to do before you ditch.
...for argument's sake, that CO2 is discovered to be an insignificant contributor to what is an almost totally natural, climatic variation. What then, will all of this posturing have achieved?
Its also very heavy and less efficient than pure diesel. The only reason its used in railway locomotives is that having an electrical connection to motors in the bogies (trucks to americans) its a LOT simpler and more reliable than mechanical linkages + gearboxes or compressor + hydraulic lines + hydraulic motors.
Solid-oxide fuel cells are a much more efficient way to burn hydrocarbons then conventional combustion engines. An electric airliner that used solid-oxide fuel cells could potentially get more range for the same weight of fuel - and unlike with batteries, you're not trading off fuel mass.
I share the opinion of numerous previous posters, when Airbus shows us their electric 380 with 45 minute of flight time, they'll be laughted at. 45 minutes just isn't enough, they should drop that stupid electric fan idea.
AFAIR, you're not allowed to plan a flight with less than 30 minutes of fuel left at landing. So this is for very short hops indeed. Source: Have a (mostly unused) pilot's license.
But they have been successfully used on German zepplins in the 1930ties. They are a bit heavier than otto engines of the same hp, but that is offset by needing 40% less fuel. Something that matters a lot when doing transatlantic flights. They are also more reliable and more suitable to turbo charging, wich is essential on greater hights.
Jet engines are already a kind of turbo diesel engines, so that would just be a step back
Are fuel cells+electric fans more efficient than running jet engines on hydrogen directly? I can see 1 point in doing it: the water generated by fuel cells is not directly released high up in the sky and thus there will be no contrails. Contrails are really a problem in many areas blocking sunlight during some wheater conditions.
or twisted rubber band.....
Solid-oxide fuel cells are a much more efficient way to burn hydrocarbons then conventional combustion engines. An electric airliner that used solid-oxide fuel cells could potentially get more range for the same weight of fuel - and unlike with batteries, you're not trading off fuel mass.
Have they managed to extend the lifetime of fuel cells that work on anything other than hydrogen? That has always been the problem with burning hydrocarbons in fuel cells.
Where did all the news about fuel cells go??
A few years ago they were on Slashdot every week.
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Airships get their bouyancy for free. An aircraft has to drag its weight up into the sky using fuel so the last thing you want is a heavy engine with poor hp/ton ratio.
But a trainer should be paying for itself and this will spend too much time on the charger for that.
But the flight school won't be impressed with 45 min flight and an hour (is that all?) on the ground to recharge.
Non experimental-versions of this aircraft (such as potential trainer that you mention), could implement swappable batteries.
(As it's the case with Tesla Model S. The battery is designed to be swappable and Tesla is working around a "fresh battery rental" system).
In that case, the thing which is spending time on the charger is the spare battery pack, while the other pack is flying in the air craft.
Have 2 (or 3) sets of battery rotating, and you don't need to think about charging times.
The time schedule now looks much more like fuel (except you swap in a fresh battery, instead of pumping fuel).
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I think this makes total sense. If we see hydrogen fuel cells it may rather be airplanes before ground vehicles. The biggest problem with hydrogen in cars is not only the lack of a distribution network, but also the leakage. Leave the car parked for a month and it is empty. This would not happen with a plane, fill it up and "burn" it more or less immediately. The airport is already a place where specialized fuels are delivered and stored, hydrogen may not be so much an added hassle.
No idea - but the general point was that pure electric air propulsion is a technology that doesn't exist in a vacuum. There's lots of ways it could become viable.
I don't see why a heavier engine is a problem if that means lugging tons less fuel.
I think you're being optimistic. Diesel might have better fuel economy per unit volume than petrol or avgas, but diesel fuel is somewhat denser and therefore heavier than both.
Whilst you highlight some of the advantages of electric over diesel, I don't buy that that's the whole reason for diesel electric trains. I suggest the advantages include efficiency, just as with hybrid cars.
Why? Because the first diesel electric locomotives were shunters, and they don't power up the bogies or a train, they just push or pull. So your explanation wouldn't cover it.
Fuel cells work, but they are vastly more expensive than batteries. Most people just got bored of waiting for a breakthrough that would make them cheap enough to be viable.
Whilst you highlight some of the advantages of electric over diesel, I don't buy that that's the whole reason for diesel electric trains. I suggest the advantages include efficiency, just as with hybrid cars.
Why? Because the first diesel electric locomotives were shunters, and they don't power up the bogies or a train, they just push or pull. So your explanation wouldn't cover it.
Boggies = trucks = wheels. Grandparent is talking about getting power from the engine to the wheels is simpler using diesel electric tech than a pure diesel tech. You still need to get power to the wheels of the locomotive when you're shunting. However with diesel electric you don't need a 1000HP clutch.
Interestingly I see things like this around for shunting (eg: at a processing plant), which are not diesel electric:
http://www.trackmobile.com/com...
Agree. Fuel cells actually make a lot of sense in any kind of transportation situation. They're far more effective than batteries at storing power. They're just not all that practical yet. As far as I'm aware the only fuel cell that REALLY works reliably is the hydrogen-oxygen fuel cell.
carbon footprint is worse.
Jet engines themselves are a step back from high bypass turbofans and turboprops. One of the rules of thumb for aircraft engines is that a bigger fan spinning slower is more effecient than a smaller fan spinning way faster. But the the prospect of having basically all fan driven electrically without an obstruction from compressor, fuel handling, etc may swing the balance in favor of diesel electric (ie one turboshaft driving a generator running the fans) in some cases.
You kind of forgot that a big part of the thrust in a jet engine and to a lesser degree also in turbofans comes from the thermal expansion of gasses as a result of burning fuel. That factor falls away with electric fans.
Install bigger motors, ditch the batteries, and use a 100KW fuel cell ot power it...then it is a workable aircraft. ;-D
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